I had tested CYA maybe 3 or 4 weeks ago at close to 60. We have had some rain and some heavy rains lately, and i had to drain out some water (2 inches or so), but now the CYA s testing at 30. That seems pretty drastic as half the pool did not drain and refill. Does that sound normal? 13k Pool, Central Texas.
CYA yoyo-ing
- Thread starter poolbel
- Start date
- May 3, 2014
- 59,249
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
It does not sound normal. Have you brushed or run a robot in the pool since you had the rains?
+1. If you had Leslies double check your results (or vice versa) it makes perfect sense. If they ran both tests, it makes even BETTER sense. 
Interested in following this. My CYA plummeted from 35 to less than 20 (10ish?) over 2 weeks since the last test. No rain. Usual splash out and evaporation replacement. I just finished a mustard algae slam and all appeared to be back to normal. It was ahead of schedule for the CYA test (and some others) but decided to do one as rainy season is just starting and heavy rains are predicted over the next few days. I am also using the Pentair (Pro-11) test kit (the only one available where I live) and have re-tested with a friends Pentair kit (same result).